The shell itself is made from broadened and flattened ribs, fused to parts of the turtle’s backbone (so that unlike in cartoons, you couldn’t pull a turtle out of its shell).

Pictured: a turtle with a really cool shell.Dan Nosowitz is a freelance writer and editor who has written for Popular Science, The Awl, Gizmodo, Fast Company, BuzzFeed, and elsewhere. He holds an ...